1. Field of the Invention
The present invention relates to a prism sheet, and more particularly to, a prism sheet having diffusing and condensing functions that may prevent a moiré phenomenon and a method for fabricating the same.
2. Discussion of the Background
Liquid crystal display (“LCD”) devices are widely used in various industrial fields because they are generally lightweight and compact and require low power consumption. Such an LCD device includes a liquid crystal (LC) panel in which liquid crystal cells are arranged in a matrix between two transparent substrates, a driving circuit to drive the LC panel, and a backlight unit to supply light to the LC panel.
The backlight unit includes a lamp to generate light, a housing surrounding the lamp, a light guide plate to guide light emitted from the lamp toward the LC panel, a reflector sheet arranged below the light guide plate, and a plurality of optical sheets stacked above the light guide plate.
The optical sheets include a diffuser sheet, a prism sheet, and a protector sheet stacked sequentially above the light guide plate. Here, two or more diffuser sheets and two or more prism sheets may be arranged according to a desired product characteristic. Multiple diffuser sheets result in a thicker backlight unit. The prism sheet may have a prism pattern in which a mountain and a ravine are formed in turn. However, if the pitch of the prism mountain and the pixel pitch of the LC panel overlap, a moiré phenomenon, which is wave-like pattern interference, may occur.